1. Field of the Invention
This invention relates to telephone disabling devices and has particular reference to lockable means for selectively preventing outgoing calls from being made by unauthorized persons.
2. Description of the Prior Art
Present day telephone systems normally permit toll calls as well as local calls be made by means of the conventional telephone sets having dialing devices comprising either depressible touch tone keys or finger operated dials. Thus, small children or other unauthorized persons may inadvertently or otherwise accumulate substantial toll charges which the subscriber may be charged for.
Heretofore, lockable telephone disabling devices have usually taken the form of a key lock insertable in a finger opening of a finger operated telephone dial. However, such disabling devices can be circumvented by proper repetitive depression of the hand set control switch plungers. Also, such devices cannot be used with touch tone telephones utilizing depressible keys for making outgoing calls.
Other lockable telephone disabling devices have been proposed utilizing a device for holding depressed the hand set controlled switch plungers. Although such devices are generally satisfactory in preventing outgoing calls, they also prevent two-way conversation.
Still other lockable telephone disabling devices have been proposed comprising lockable switch means for opening or closing the telephone circuits. These generally require physical modification of the telephone and certain electrical connections which could possibly interfere with the telephone circuitry.